Another way of cleaner public transportation: Four-stroke high torque CAE (Compressed Air Engine) performance analysis and CAE bus

Abstract

The vehicle industry is currently developing toward using new ecologically-friendly energy. Although the energy density of compressed air is not high, it is very ecologically friendly and can be used as a power source to drive vehicles. Therefore, it should still have application prospects in some specific applications. The purpose of this paper is to fill the gap in the research field of high torque CAE for a large vehicle and explore the application possibility of CAE in the field of new energy vehicles for public transportation. A four-stroke six-cylinder high torque CAE (Compressed Air Engine) was proposed. The calculation model of this CAE was constructed, the dynamic characteristics were theoretically analyzed, a prototype engine was manufactured and tested on the engine bench system, and the on-road test of the bus equipped with CAE was carried out. The results show that CAE has the characteristics of obtaining more significant torque at low speed. The bench test results of torque and power are in line with the changing trend of CAE dynamic performance predicted by calculation. When the inflation pressure of the prototype is 10 MPa, and the rotational speed is 650 r/min, the effective torque can reach 1032.48 N m. The CAE bus runs very stably during the on-road test. It can maintain a 60–80 km range with a load of 18 tons and a maximum speed of 69 km/h. The research of this paper can show that the compressed air engine with high power output shows excellent characteristics from theoretical analysis to vehicle tests. It is possible to use CAE to drive vehicles in new energy public transportation in the future.